Method of and means for producing dental plates



April 17 1934. J KlNSLEY 1,955,709

METHOD OF AND MEANS FOR PRODUCING DENTAL PLATES Filed May 6, 1929 fig; 3

Patented Apr. 17, 1934 sarseir series @F AND MEANS FGR PRODUCING DENTALLLATES Jason D. Kinsley, Cedar Rapids, Iowa Application May 6, 1929,Serial No. 360,961

20 Claims.

This invention relates to the making of rigid or substantially rigidcounterparts of more or less {solid objects, more especially the makingof counterparts for use in that branch of surgery known as'prosthodontia or plate-work. Among the objects of this invention are toprovide a process which will reduce the errors of operation whichare'b'ommonly introduced during the process of m a'king dentures; toprovide improved apparatus fer the purpose indicated; to provideimproved means and methods of forming substantially rigid counterpartsof rigid or semi-rigid physical surfaces; and such further objects,advantages and capabilities as will hereafter appear and as are inherentin the structure and method disclosed herein. My invention furtherresides in the combination, construction and arrangement of partsillustrated in the accompanying drawing, and, while I have shown thereinwhat is now considered the preferred embodiment of this invention, fromits physical aspect l desire this disclosure to be understood asillustrative only and not to be interpreted in a limiting sense. As thisinvention applies to prosthodontia its principal object is to provide aprocess and means whereby an individual impression tray may be :quickly,cheaply and easily constructed. It has as a further object the provisionof a process which facilitates the construction of better bite plates,or trial plates, for use in denture construction without the necessityof making a transfer of the same to or from a model of the gum- "ridge.As this method applies to plate work, I term it the non-transfer method.Among the advantages of this method are better fitting dentures, fewerfailures, greater accuracy in construe tionjelimination of a bulky stockof dental trays and apparatus required in all other methods of dentureconstruction, less time consumed by the dentist, fewer appointments withthe patient, and a. more perfect guidance for all subsequent mechanicalprocedure.

In order that there may be a more complete and better understanding ofthe following specification and claims it is deemed advisable to definecertain terms used herein in simple and comprehensive language. Theseterms are as follows: Denture patte1'n.A test plate having for its baseand supporting structure a bite unit, the concavity of which containsthe impression of the gum-ridge and the convexity supports the bite rimmaterial so formed as to reproduce the general contourof the lost teethand their supporting tissues and the crest of which registers thecorrect occlusal surface.

Fig. 5 shows the same as above with the pro= tective covering removedand the margins of the tray trimmed to the desired limitations inpreparation for the act of turning back the margin to form a smoothedge.-

Fig( 6 shows the samev with anchorage upon the convex contour, or ridge,and made rigid by a process of infiltration with a quick setting fluid.

Fig. '7 shows upper and lower bite units in relative position as when inthe mouth but before the bite-rims have been formed on the anchorages.

Fig. 8 shows an upper bite unit with abrasive rims formed upon its ridgeand covering its anchorages, now'in preparation to receive plasticmaterial within its concavity and ready for the taking of an impressionof the patients gumridge.

Fig. 9 shows a pair of completed denture patterns with the occlusalplanes ground or molded to perfection by the movement of the jaws in theact of chewing, and with retaining grooves formed across the junction ofthe two bite rims on the buccal surfaces.

Fig. 10 shows a pair of completed upper and lower denture patternsthesame being held in correct relationship to each other, as when in themouth, by a simple coupling means comprising a key-plate filled withhard wax which has been heated to plasticity and pressed against thebuccal surfaces of the pattern so as to fill the grooves while thepatterns are held in centric relation by the patient closing the jawsand holding them in normal position.

Fig. 11 shows'the inner side of the wax registry of the key-plate. Fig.12 represents a fragment of a suitable anchor strip.

In order to find out more fully the differences between the old methodand the new and the advantages of the latter, it is necessary to stateherein some of the shortcomings of the prior practice with regard to themaking of dentures.

In the first place, the commercial tray, such as is most commonly usedin practice, does not fit the gum ridge, in the vast percentage ofcases, closely or uniformly enough to effect an even and perfectdistribution of plastic material about the gum-ridge. In a largemajority of cases, it is merely an approximation but, since a fairapproximation can be secured by the use of a large number of dentalimpression trays, the method has been followed by the profession asoffering the best expedient available. In contrast to this, the specialtray of my invention is made to fit the individual case perfectly and,consequently, enables the operator to secure a perfect impression in allcases, and such special tray is made practical and useful in distinctionfrom all other special types of individual trays by reason of the hereindisclosed rapid, inexpensive and accurate process for the constructionof the same.

The bite unit serves a twofold purpose; First, holding within itsconcavity, any of the common- 1y used impression materials such asplaster of paris, modeling compound and the like; second, providing uponits convex contour, improved means of anchorage for and reinforcement ofany of the commonly used bite rim materials such as bees-wax or anabrasive. Combining in one unit the perfected impression of a patientsgumridge, on one contour of a bite unit, and the bite rim, upon theopposite contour-of the same, provides simple, easy and accurate meansby which perfect fitting dentures (dental plates) may be constructed anddelivered to the patient, with but one sitting being required for allpreliminaries to the laboratory or mechanical procedure. In thisway,-the unavoidable hazards encountered bymaking numerous transfers, asis common to all other methods of plate work, are obviated. As indicatedabove, the present method is termed a non transfer method while allother methods are referred to as transfer methods. In any course ofprocedurefor plate work, a perfect impression of the gum-ridge isessential to a perfect fit of a denture. Such an impression cannot besecured without the aid of 'a suitable impression tray which must serveas an exact means of equally distributing plastic impression material,the-same recording in minutest detail the contour and periphery of thesurfaces against which the finished denture is to rest. Such a tray iseasily provided for any case by following the herein described process,and may or may not be provided with anchorages for bite material. As asimple impression taking device, it has the above described requirementsand is applicable to any transfer method, and at the same time mayeasily be'converted into a bite unit, by constructing anchorages uponits convexity.

The transfer method is based upon the hypothesis that accuratereproductions of surface 'contours, and the relative anatomicalpositions and relations of models for a given case, in plate work, canbe accomplished by means of wax transfers from model to mouth and frommouth back to model without danger of error or misplacement. Theprocedure of the transfer method is to first construct the biteplates ofhard wax or like material upon castsor models of a patients mouth andthen remove and transfer said bite-plate from said model'to said mouthfor the purpose of determining the correct bite, after which anothertransfer is made carrying the wax bite plate back again from the mouthto the model and fixing said models and bite plates in their supposedlycorrect original relationship. This procedure proves exceedinglyhazardous to plate work as most models of human mouths have undercuts inthem to a greater or less degree. It is obvious that making a hard Waxbite plate, as above described, which is constructed by heating rigidwax to plasticity and then pressing it to close conformity to thesurface contour of the plaster model having undercuts, and allowing saidwax to cool to rigidity, constructs a plate of wax upon said model whichcannot be removed therefrom without distortion and injury to said waxplate, said model or both, a consequence which inevitably results incorresponding degrees of imperfection in the finished dentures. Suchprocedure is quite often responsible for ill-fitting dental plates.

Under the transfer methods six distinct steps in procedure are followedas described below:

1. An impression of the gum-ridge is taken by the dentist in some formof tray selected for impression taking only, and then plaster of parisor the like is poured into said impression and a model formed which isthen separated from said impression. When dentures are to be made for "iboth upper and lower jaws, the same procedure is followed in both cases.

2. Abite plate is then formed upon each mode as above described.

3. A medium soft wax bite rim is then formed by softening such wax withheat and pressing it upon the convex contour of the bite plate describedin step 2.

4. This step comprises the removal of the wax bite plate from the modelupon which it has been formed. If the bite plate is made of medium softor yielding Wax it is sure to be bent out of shape (distorted). If it ismade of hard, rigid wax it'is likely to mar the model or break the wax,under thestress of forcibly separating the two. the separation has beenaccomplished, the bite plate is transferred to the patients mouth;

5. The fifth step involves the manipulation in the patients mouth, themost common practice being to first warm the'crests of the two bite rimsso as to soften them somewhat'and then, having placed the plates in thepatients mouth, have the patient compress the said bite rims by bring.-ing the jaws to their normal centric relationship when closed. Anotherpractice, in the construction of both upper and lower dentures, is tofurrow out the center of said wax bite rims from end to end, along theircrest, and fill-said furrow with an-abrasive material such as describedabove, the object in this case being to provide meansby which thepatient can grind or'mill in his own bite to correct occlusion. This isa very excellent object, but there is very inadequate provision'foraccomplishing same, as the softening wax rim, while at the temperatureof the mouth, yields under the stress of the jaws in the act of chewingor milling, and obviously, this causes breaking and crumbling oftheabrasive and, in case this does not occur, the softened wax smearsoverthe abrasive and interferes with the milling procedure. In either ofthe'above practices the bite plate is likelyto be distorted by theremoval and transfer from its respective model to the mouth andconsequently there results inaccuracy in either the bite taking orgrinding process within the mouth. After the grinding-in or bite takingoperation, the bite rims are attached together in the patients mouth'intheir supposedly correct relation.

6. This step is to transfer the bite rims, attached After together asindicated in step 5, back to their original positions, each upon itsrespective model. This step is exceedingly hazardous and doubtful and inaltogether too large a percentage of cases the plates are never replacedwith technical exactness due to the distortion of the wax plates or themodels or both. This leaves the dentist in .the position of having toguess at their proper relationship, fix them in the position which heguesses to be correct and take his chances on the final outcome. Themisplacement of either upper or lower or both models within theirrespective bite plates, to the slightest degree, in this step, is sureto result in an equivalent degree of inac curacy in the finalrelationship of the dentures in the patients mouth. Therefore, thehypoth esis referred to above proves to be unsound.

An injury to a plaster model by reason of forcible removal of a rigidwax bite plate therefrom is certain to be registered in the tissuecontacting surface of the finished denture and to cause no littledistress to the patient and consequent annoyance to the dentist, who isusually at a loss to know just where to relieve the trouble, and oftencauses an added injury to the plate in the attempt to remedy thedifficulty.

It will readily be seen that the non-transfer method obviates every oneof the causes for inaccuracy, miss-fit, distress and annoyance asdescribed above in steps 4, 5, and 6, as these steps are entirelyeliminated from the procedure followed in the non-transfer technic, afact which is made possible by the invention of the bite unit, with theaccompanying process for making the same.

7 In the following description of the various steps in the non-transfermethod, it is understood that the operations for either upper or lowercases are practically the same, and that, unless a contraryinterpretation of the language is necessary, reference to either upperor lower is intended in a comprehensive sense and is meant to includeboth.

Reference will now be made in greater detail to the annexed drawingwherein the lower tray matrix is indicated by the numeral and the uppertray matrix by the numeral 6. These matrices are formed of a porous,pliable material capable of being manually moulded by pressure toconform approximately to the gum ridge and of remaining in the mouldedform after being removed from the mouth. This material should be capableof being rendered rigid or substantially rigid by infiltration in theapplication of a coating of quick setting fluid after it has beenremoved from the mouth. After the matrix has been manually moulded bypressure to conform approximately to the gum ridge so that it takes theproper conformation, it may be rendered substantially rigid so as tokeep this shape while under the stresses to which it is later subjected.In practice, the preferred material is a light, rather close-meshedbrass wire-cloth, which, when annealed, may be pressed by the fingersclose to the patients gum, and conformed thereto. It sometimes happensthat there is an excess of material at the point indicated by the line 8in Figs. 2 and 3 and this excess may be removed by cutting away aportion of the screen. Removing this excess of material will make itpossible to fit the matrix more closely to the gum ridges and do awaywith some buckling which might otherwise be present.

As a protection against any scratching of the tissues of the mouth bythe sharp edges of the woven metal matrix, a soft, pliable covering 9 issupplied which envelops the matrix, as illustrated in Fig. 3. Anexcellent material for this purpose is chamois skin, but a thinnermaterial is preferred which will permit the matrix to be fitted moreclosely to the gum-ridge. In Fig.- 12 there is shown a metallic strip 10having tangs 10a extending therefrom. In Fig. 6 such a strip is shownsecured to a special tray to form a bite unit. The ends of strip 10 areindicated at 1012 in Fig. 6 as being bent down over the edge of the trayto hold the same assembled with the tray. Also some of the tangs areindicated at 100 as being bent around the edge of the tray for thispurpose. The remaining tangs 10a serve as anchorages for the bite rims11 and lie, the finished occlusal surface of which is denoted by numeral111). A key-plate 12 (Figs. 10 and 11) having hard wax adhering theretois used to tie two denture patterns together as indicated in Fig. 10.the patterns having grooves 13 carved therein across the plane of themeeting surfaces to assure perfect matching of the patterns in case itshould be necessary later to match them. These grooves also assist inholding the patterns together by reason of providing points ofattachment for the wax. Their use will be referred to more fullyhereinafter. If desired the patterns may be further secured together bya few drops of sealing wax as indicated at 14.

In practicing this method, the dentist, at the first sitting of thepatient, selects the proper size of tray-matrix, enveloped by aprotecting shield 9, as heretofore indicated, and places this in thepatients mouth, pressing the same, with his fingers, against the palateand into close conforinity with the gum-ridge, the margins of the matrixbeing then folded up around the gumridge to a preliminary tray-likeform, as shown in Fig. 4. After this the operator, with apencil or thelike, outlines the margins in conformity with the periphery of his case.The formed matrix is then removed from the mouth and trimmed to theperiphery, a slight margin being left to be turned over so as to form asmooth edge around the matrix. The covering is then removed and the edgeof the matrix is rolled back to the line of the periphery, providingample clearance for all muscle attachments. After this op eration thematrix may be replaced upon the gum, for final perfection of form, ifthe operator desires. He then removes the formed, perfected matrix fromthe mouth and dips it in a bath of soldering flux, then into a bath ofmolten solder or babbit metal, or the like. The tray-matrix is thenremoved from the molten metal and allowed to cool so that the metalhardens. For this purpose of stiffening the tray, various fluid materials, which harden quickly may be utilized but, in practice, the mostsuitable material I have found is solder or babbit metal which,upon'being cooled, leaves a substantially rigid impression tray whichmay or may not be provided with anchorages upon its convex contour asthe operator desires and as shown in Fig. 6. I

By this process the tray matrix becomes a special tray adaptable to allmethods of plate work now in practice. As a further means of obviatingthe transfers herein referred to (see transfer method above), thedentist now forms anchorages upon the convex surface of the specialtray. This may be done by the addition of a strip of metal having tangsthereon, as shown in Fig. 12. The strips 10, with their tangs 10a, serveas reinforcements for the bite rim' material and the perfected tray. Thebite-rim material may be either wax, abrasive, or any other suitablematechanical constructions.

rial. The dentist has now constructed a bite unit (see Fig. 6) andproceeds to procure a fect impression'of the gum ridge within theconcavity of said bite unit and a perfected bite rim upon the convexitythereof. 'It matters little which is done first.

We will assume first that the structure of Fig. 6 has been made andthat'it is'desired to take an impression of the gum ridge correspondingthereto. In doing this the concavity ofthe bite unit is charged withimpression material, prefeilabl y modeling compound and then the same isinserted in the mouth and pressed over and about the gum ridge in evenand uniform distribution, and in close conformation therewith. When theimpression has been taken, the bite unit is removed from the mouth and abite rim constructed thereon, forming the structure illustrated in Fig.8, or, as above stated, said bite rim may be constructed before thetaking of said impression. This bite rim may be made from wax, abrasive,or the like. It will of course be understood that this will be for bothupper and lower gum ridges. The impression material isaccurately formedwithin the concavity of the bite unit and is rigidly held thereby, beingsubstantially a part thereof. Afterthis, the bite unit is removed fromthe'mouth and has upon its ridge and over and about the upstandinganchorages 10a a bit rim 11 or 11a, preferably of abrasive materialwhich is' held rigid by the anchorages referred to above. This havingbeen done for both upper and lower gum ridges, the two unitscorresponding to Fig. 8 are placed in the patients mouth as indicated inFig. 9 and the exteriors thereof are formed, the two units having thesame general form and positional relationship as that of the naturalteeth and their supporting tissues. The patient is then instruct-- ed toperform the act of chewing upon the crest of the abrasive rims and thisgrinds and perfects the occlusal surface. 11b. Retaining grooves 13 arethen carved across the junction of the two bite-rims as indicated inFig. 9 and the rims are attached together by means of a keyplate 12filled with hard wax heated to plasticity and pressed over the junctionof the rims, the same entering the grooves 13 so that perfect registrycan always thereafter be secured. The patient is now dismissed and willnot need to call again until the dentures are finished, since thedentist now possesses perfect denture patterns for his patientsartificial teeth. These serve as an infallible guide for all subsequentme- The bite, contour, occlusal surface, all registrations and markingshe may desire, and the perfected impressions for his case are suppliedby the denture patterns. As the models have not yet been poured, it isobvious that no transfers as described for all other methods are hereinemployed. -The next step after completing the denture patterns is topour the models in the impressions thus taken within the bite units, andwith the bite units held in relation by the key plate 12; and inconjunction with an "articulator.

The sequence of operations thus described at length does not in practiceconsume a great amountof time. Without subjecting thepatient to a verylong wait it is possible to dismiss the patient after the firstappointment and at the next call deliver to him an accurately fittingand completed pair of dental plates.

Having thus described my invention, I claim.

1. The described method of producing'a dental impression tray or form,which consists in pressing a sheet of thin, pliable material about thegum, withdrawing it and rendering it rigid by applying to it a liquidwhich becomes hard on solidifying.

2. The described method of producing a dental impression tray or form,which consists in pressing a sheet of thin, pliable material about thegum, withdrawing it and rendering it rigid by a bath in molten metal.

3. The described method of producing a dental impression tray or form,which consists in pressing a sheet of thin, pliable material about thegum overan interposed sheet of soft and limp material, withdrawing theadherent sheets, separating them, and rendering the formed sheet rigidby the application of a solidifying liquid.

4. The described method of producing a dental impression tray, whichconsists in molding by pressure about the gum a sheet of thin, pliablematerial, applying to the form so made a hardsetting liquid to fix itsshape, applying to the stiff form an anchorage for plastic material, andfirmly connecting the form and anchorage.

' 5. An improved method of producing a piece of dental apparatus, whichconsists in forming by pressure about the gum a sheet of thin, pliablematerial, fixing its 'form by the application of a hard-setting liquid,attaching to the ridge an upstanding anchorage for plastic material, andforming on the bite unit thus formed and over the anchorages a bite-rimof plastic material impregnated with an abrasive.

6. An improved method of producing dental bite-units. which consists informing by pressure about the gum a sheet of thin, pliable material,

fixing its form by the application of a hard-setting liquid, attachingto the ridge an upstanding anchorage for plastic material, forming onthe bite unit and over the anchorage a bite-rim of plastic materialimpregnated with an abrasive, and charging the matrix with an impressioncompound.

7. A special tray formed of light and pliable woven wire molded to formabout the patients gum, and said wire being embedded in rigid metalwhereby the wire is fixed in form. 8. A bite unit formed of light andpliable woven wire molded to form about the patients gums, said wirebeing embedded in rigid metal whereby the wire is fixed in form, andprovided along its ridge with anchoring projections to retain a bite-rimof plastic material.

9. The described method of determining the bite in the forming andfitting of dental plates, which consists in pressing a tray matrix toconformation with the gum ridge, rendering the same rigid by theapplication of a solidifying liquid, building a bite rim on each ridgeof hardening plastic material impregnated with m abrasive, perfecting animpression of each respective gum-ridge, and with both denture patternsin the mouth, finally grinding the rims to the biteline by the naturaland varied movements of the patients jaws.

10. The method of producing a removable and replaceable solidcounterpart of a solid or semisolid material surface contour by forminga matrix of pliable porous material about it and infiltrating smd matrixmaterial with a quicksetting liquid which, on solidification, rendersthe matrix material solid and rigid like.

11; The method of producing a special tray which consists in pressing amatrix of pliable porous sheet material about the gum, withdrawing thesame, and rendering it hard and firm by infiltration with fluent metalwhich quickly solidifies at normal temperature.

12. The method of producing a dental tray which comprises covering amatrix of thin pliable porous material with a sheet of tough flexiblematerial and, while thus covered, pressing it to form about the gum,removing it therefrom, withdrawing said covering, and rendering saidmatrix solid. and firm by application of a fluid material whichsolidifies.

13. The method of procuring the bite which consists in shaping a matrixof pliable porous material to fit the gum-ridge, rendering said matrixhard by applying thereto a solidifying fluid material, providinganchorages on the convex surface of the shaped matrix, charging theconcavity thereof with impression material, taking an impression of thegum ridge therein, forming a bite-rim upon and about the anchoragesthereof, and finishing the bite-rim.

14. The method of making denture patterns which comprises fashioningsheets of pliable porous metallic material into close conformity withthe gum-ridges of a patients mouth, infiltrating the so shaped materialwith fluid metal which becomes hard at normal temperature, removing thesame and permitting hardening to take place, providing the convexsurface of the shaped material with anchorages, forming over and aboutsaid anchorages an abrasive bite-rim for each pattern, lining theconcavity of each with impression material, placing the patterns one ata time in the patients mouth each upon its corresponding gum-ridge,manipulating each pattern separately so as toeffect an equal distribution and adaptation of said material to and about said gum-ridge,and causing the crests of the bite-plates to be ground within thepatients mouth, each against the other until the correct occlusalsurface is formed upon each of the said crests.

15. As an article of manufacture, a piece of porous, felt or fabric-likematerial, capable of being made rigid upon infiltration with arapidlysolidifying fluent material, and being of a form suitable to beapplied to a human tissue and,

when so applied, to be shaped thereto, said material having a toughflexible substance enclosing the edges thereof for the protection of thebodily tissues when applied thereto, said substance being easily removedfrom said material after the latter has been molded to desired form.

16. An article as defined in claim 15 which is cut to a formapproximating the periphery of a gum-ridge and has an area suificient topermit modeling same to flt and completely cover the gum-ridge.

17. As an article of manufacture, a piece of porous material capable ofbeing made rigid upon infiltration with a rapidly solidifying fluentmaterial, the same being of a form and physical character suitable to beapplied to a human tissue and, when so applied, to be shaped theretoand, when so shaped, to retain its form when being handled, said porousmaterial having a covering normally preventing access of air thereto,said covering material being readily removable for use of the porousmaterial.

18. The method of producing a bite-unit which consists in forming aboutthe gum-ridge a matrix of pliable, porous material, fixing its form bythe application of a hard setting fluid material, providing its ridgewith an upstanding anchorage for bite-rim material, and forming upon andabout said anchorage any desired form of bite-rim.

19. A method of quickly producing a special dental impression tray whichcomprises forming a sheet of porous pliable metallic fabric to fit adental tissue surface of which an impression is desired, andinfiltrating the formed fabric with fluent metal which will coheretherewith and become solid.

20. A method of quickly producing a special dental impression tray whichcomprises forming a sheet of porous pliable metallic fabric to fit adental tissue surface of which an impression is desired, treating itwith a soldering flux, infiltrating said fabric with a fluent metal, andremoving the fabric into such conditions as will cause the fluent metalto quickly become solid and coherent with said fabric.

JASON D. KINSLEY.

